This invention relates to an apparatus and method for performing an osteotomy. More particularly, it relates to an apparatus and method which allows angled cuts and implant insertions to be performed with accuracy.
Certain bone related problems can be corrected by removing a wedge of bone and realigning the remaining bone segments. This technique is generally known as osteotomy. Several techniques exist for performing osteotomy, but in each case it is generally necessary to perform the cuts accurately to ensure correct realignment of the bone. The cuts should be planar so that severed bone faces mate uniformly to promote rapid and structurally effective mending of the bone.
High tibial osteotomy has become an established means of treating unicompartmental degenerative arthritis of the knee. This technique aligns the lower extremity such that the axis of weight bearing is shared between the medial joint compartment and the lateral joint compartment. Thus, in cases where arthritis predominantly affects the medial joint compartment, a high tibial osteotomy directs the forces of weight bearing through the healthier lateral side of the joint, leading to relief of pain and discomfort. The osteotomy, once completed, is generally held by a staple implant through one or more cortices.
It is important that osteotomy cuts be performed accurately and that the completed osteotomy be stabilized in order to promote rapid healing and avoid prolonged postoperative immobilization in a cast. Prolonged immobilization in a cast can lead to persistent stiffness and prolonged rehabilitation. Accurate cuts also relieve pain and provide better clinical results, such as a better gait and avoidance of total knee arthroplasty.
Kirkley (U.S. Pat. No. 4,335,715, Jun. 22, 1982) relates to an apparatus wherein a pair of pins positioned on an arcuate track are inserted into the bone to serve as a guide for the surgeon in making cuts. Chambers (U.S. Pat. No. 4,349,018, Sep. 14, 1982) discloses an assemblage for guiding saw cuts to be made during a proximal tibia osteotomy or a total knee replacement operation. Slocum (U.S. Pat. No. 4,565,191, Jan. 21, 1986) relates to an apparatus for performing cuneiform osteotomy which includes a jig and an osteotomy guide. Reese (U.S. Pat. No. 4,750,481, Jun. 14, 1988) relates to a set of appliances which include a follower adapted to be positioned within a first saw cut and a saw guide movably positionable with respect to the follower and adapted to be set and held in a position to guide the saw for a second cut. Comparetto (U.S. Pat. No. 4,952,214, Aug. 28, 1990) relates to a saw guide with two intersecting slots, wherein the main slot is arcuate and is used to make a curved cut in a bone, and the other slot is either straight or arcuate and is used to cut a wedge-shaped section from the bone. Hofmann et al. (U.S. Pat. No. 5,021,056, Jun. 4, 1991) relates to an apparatus for performing osteotomy which includes a transverse alignment guide, an osteotomy guide, and a fixation plate. Schreiber (U.S. Pat. No. 5,246,444, Sep. 21, 1993) relates to an osteotomy device and method that allows a surgeon to establish a reference external to the bone as to the position of the apex and angle of the wedge to be cut and then to make use of an integral saw guide to translate those references into the bone as saw cuts. All references cited herein, including the foregoing, are incorporated herein in their entireties.
It is an object of the present invention to provide instrumentation which allows a surgeon to make accurate transverse and angular cuts. In particular, it is an object to provide instrumentation which allows a surgeon to produce smooth osteotomy surfaces which come together in a flush manner when the osteotomy is closed. It is yet a further object of the present invention to provide a method of performing osteotomy.